2003 SSEI bad MAF?
#1
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2003 SSEI bad MAF?
What is a "normal" MAF reading? My car has died on me twice now, both times I've managed to get it restarted but it won't idle (300-400 RPM till it dies unless I give it gas). I can use the accelerator to keep it idling at a light and limp it home slowly but I think it'* running rich (black smoke). After it did it the first time I got home and it ran fine, I drove it for 2 weeks before it happened a second time and I had a scanner with me. I noticed that the boost gauge goes to 0 at idle when this happens. I scanned it and found the MAF readings at 0 so I replaced the MAF (thank you lifetime warranty), but the readings I'm getting are still very low .08 g/*. The car is bone stock, so far I've verified 12V and ground to the MAF and traced the wire from the MAF to the PCM at 0 ohms, so I don't suspect a wiring issue or a bad ground. Any assistance the group can provide is appreciated.
Brent
Brent
#2
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Not exactly sure what the readings should be, but those seem low.....lifetime warranty? Some of those after market MAF'* have short lifespans, and sometimes the replacements are bad right out of the box...
Does it run better with the MAF disconnected?
Watch the O2 readings when the car acts up....if they are bad, disconnect the MAF and see if the readings of the O2 go back to "normal"....if they do, it looks like the MAF....
Like I said, aftermarket MAF'* have been problematic.....If you do not find a vac leak anywhere that would skew the readings, I would be leaning towards that...
Does it run better with the MAF disconnected?
Watch the O2 readings when the car acts up....if they are bad, disconnect the MAF and see if the readings of the O2 go back to "normal"....if they do, it looks like the MAF....
Like I said, aftermarket MAF'* have been problematic.....If you do not find a vac leak anywhere that would skew the readings, I would be leaning towards that...
#5
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Well, on my 3rd MAF I saw that the MAP readings were being affected also. Does anyone know if the MAP drives the stock boost gauge? I've discovered an intermittent bad ground for both the MAF and the MAP, but it'* not consistent enough that I've found the problem yet. I'm fortunate that I have another vehicle to drive, so the Bonneville has spent a lot of time hanging out in the garage lately. When the boost gauge reads 0 at idle it'* a false reading, pulling a vacuum line and checking it with a handheld gauge I do have vacuum at idle. I haven't decided if I want to pull the wire loom apart to find the problem or cut the wires and reground them. Does anyone have a good wiring diagram that shows everything that uses the ground point on the front of the engine below the coil packs? I assume all of those grounds are suspect at this point but I don't know where all of those grounds go. I haven't checked the body to engine ground yet, but I should have time to tackle it again later this week.
To answer the questions about codes, this is what I've seen:
P0101 Mass/Volume Air Flow Circ Range/Perf
P0102- Mass/Volume Air Flow Circ Lo Input
P0107- MAP/Baro Pres Circ Lo Input
To answer the questions about codes, this is what I've seen:
P0101 Mass/Volume Air Flow Circ Range/Perf
P0102- Mass/Volume Air Flow Circ Lo Input
P0107- MAP/Baro Pres Circ Lo Input
Last edited by Brent; 07-12-2015 at 10:49 PM.
#6
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Well, now I've discovered that the MAP gets its ground through the ignition control module. I'm not sure the ignition control module is good, but I am sure that the ground point on the front of the engine is now good. Still researching this but, I see a replacement car in my future at this point.
#7
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Resolution: I gave up and took the car to the dealer. After troubleshooting they diagnosed a bad PCM. New PCM from GM was backordered and $1500! Bought a PCM off Ebay for $120 and paid $130 to have it installed and the sensors relearned. So far (2 weeks now) it'* running fine.
The following 2 users liked this post by Brent:
GunsOfNavarone (08-22-2015),
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